Vault terminal computercraft

local oldPull = os.pullEvent;
os.pullEvent = os.pullEventRaw;
term.clear()
term.setCursorPos(1,1)
correctpass = "Open"
write("Enter Password: ")
pass = read("*")
if pass == (inst) then
write("Vault door cycling sequence initiated")
redstone.setOutput("back", true )
sleep(7)
redstone.setOutput("back", false )
os.shutdown()
end
write("Incorrect Password")
sleep(3)
term.clear()
term.setCursorPos(1,1)
textutils.slowPrint("Terminal Locking Down in 3... 2... 1...")
sleep(.5)
os.shutdown()
os.pullEvent = oldPull;